IRAQI forces have battled Sunni militants along a string of fronts, including at Saddam Hussein’s hometown Tikrit, as the United Nations readied a massive aid operation for displaced Iraqis.

Kurdish and federal forces, who wrested back control of Iraq’s largest dam, fought jihadists in the country’s north on Tuesday, buoyed by intensifying US air strikes and Western arms deliveries.

Other security forces backed by militiamen and tribesmen are also fighting jihadists in flashpoints north, west and south of Baghdad, officials said.

The counteroffensives against the militants came as the UN refugee agency said it was launching a major operation this week to help “close to half a million people” who have been displaced.

US President Barack Obama hailed the recapture of the Mosul Dam but warned Baghdad that “the wolf is at the door” and said it must move quickly to build an inclusive government.

The dam was the biggest prize yet clawed back from the Islamic State (IS) jihadist group since it launched a major offensive in northern Iraq in June, sweeping aside Iraqi security forces.

Aid operation ... displaced Iraqi women try to catch clothes provided by a charity at a new camp in Feeshkhabour town.Source:AP

“This operation demonstrates that Iraqi and Kurdish forces are capable of working together and taking the fight to (IS),” said Obama.

“If they continue to do so, they will have the strong support of the United States of America,” he promised, in his clearest signal yet that the 10-day-old US air campaign was far from over.

Fighting erupted on Tuesday in the area surrounding the dam and US warplanes carried out fresh strikes targeting IS, a senior officer in the Kurdish Peshmerga forces said.

US experts have warned a breach of the dam could result in a flood wave at the city of Mosul to its south and cause flooding along the Tigris River all the way down to Baghdad.

As anti-jihadist forces tried to reclaim ground lost earlier this month in the north, the government launched an operation to recapture the city of Tikrit, further south.

“The Iraqi army and (Shi’ite) volunteers, backed by Iraqi helicopters, are taking part” in the operation to retake the hometown of executed former president Saddam Hussein, a high-ranking army officer said.

Fierce fighting ... a Shiite fighter backs the Iraqi army in the fight against Islamic State (IS) militants after retaking control of an area in the Jurf al-Sakher district.Source:AFP

Tikrit fell on June 11 and has since been controlled mostly by Sunni militant groups, including former members of Saddam’s ruling Baath party.

The government has made Tikrit a priority but has already failed twice to retake it.

In the north, members of minority groups including Christians, Yazidis, Shabak and Turkmen, remain under threat of kidnap or death at the hands of the jihadists, while tens of thousands of others have fled, prompting the UN to announce the major aid operation.

“Conditions remain desperate for those without access to suitable shelter, people struggling to find food and water to feed their families, and those without access to primary medical care,” said Adrian Edwards, spokesman for the UN refugee agency UNHCR.